VAPOUR-LIQUID INTERFACE TRACKING AND CONDENSATION INDUCED WATER HAMMER PREDICTIONS

Abstract

A numerical model for the simulation and analysis of the water hammer in the pipe two-phase flow is developed. The modelling is based on one-dimensional homogeneous model of two-phase flow, tracking of the interface between the steam volume and water column and modelling of the direct condensation of steam on subcooled liquid. Mass, momentum and energy conservation equations are solved by the method of characteristics. The interface of steam and water column is approximated with the cross section area of the flow channel. The fluid particle and steam-water interface tracking are obtained through the energy conservation equation solution with the third degree accurate numerical scheme. The value of thermodynamic quality is used to determine whether the observed computational region is filled with water, two-phase mixture or steam. The term in the energy conservation equation, that contains information about the heat exchanged between steam and liquid phase through condensation, is determined by the local balance of the heat transfer over the steam-water interface. The transient friction is included in the momentum equation due to intensive accelerations of the liquid column. Model is applied to the simulation and analysis of the air-water interface propagation in the experimental apparatus of oscillating manometer and the condensation induced water hammer in an experimental facility.